The stormwater system is often confused with the wastewater treatment system, but these are two separate systems. Water from sinks, showers, toilets, etc. travels to the Wastewater Treatment Facility. Water that flows through the storm drain often ends up in the nearest lake or stream without treatment, as these drains are designed to help prevent flooding.
How can you help? Use leaves as a natural fertilizer instead of harsh chemicals and pick up trash to help prevent pollution in our local waterways.
Original source can be found here.